ATMEGA48A-AU Atmel, ATMEGA48A-AU Datasheet - Page 29

• Manufacturer Part Number: ATMEGA48A-AU
• Description: IC MCU AVR 4K FLASH 32TQFP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA48A-AU

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 23
• Program Memory Size: 4KB (2K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 256 x 8
• Ram Size: 512 x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 32-TQFP, 32-VQFP
• Controller Family/series: Atmega
• No. Of I/o's: 23
• Eeprom Memory Size: 256Byte
• Ram Memory Size: 512Byte
• Cpu Speed: 20MHz
• Rohs Compliant: Yes
• Processor Series: ATmega
• Core: AVR
• Data Bus Width: 8 bit
• Data Ram Size: 512 B
• Interface Type: TWI, SPI, USART
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 23
• Number Of Timers: 3
• Operating Supply Voltage: 3.3 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Operating Temperature Range: - 40 C to + 85 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

8271C–AVR–08/10
Figure 8-2.
The Low Power Oscillator can operate in three different modes, each optimized for a specific fre-
quency range. The operating mode is selected by the fuses CKSEL3...1 as shown in
on page
Table 8-3.
Notes:
The CKSEL0 Fuse together with the SUT1...0 Fuses select the start-up times as shown in
8-4.
Table 8-4.
ATmega48A/48PA/88A/88PA/168A/168PA/328/328
Oscillator Source /
Power Conditions
Ceramic resonator, fast
rising power
Ceramic resonator, slowly
rising power
Ceramic resonator, BOD
enabled
Ceramic resonator, fast
rising power
Ceramic resonator, slowly
rising power
Frequency Range
1. This is the recommended CKSEL settings for the difference frequency ranges.
2. This option should not be used with crystals, only with ceramic resonators.
3. If the crystal frequency exceeds the specification of the device (depends on V
29.
8.0 - 16.0
0.4 - 0.9
0.9 - 3.0
3.0 - 8.0
(MHz)
Fuse can be programmed in order to divide the internal frequency by 8. It must be ensured
that the resulting divided clock meets the frequency specification of the device.
Crystal Oscillator Connections
Low Power Crystal Oscillator Operating Modes
Start-up Times for the Low Power Crystal Oscillator Clock Selection
Start-up Time from
Power-down and
C2
C1
Power-save
258 CK
258 CK
1K CK
1K CK
1K CK
Capacitors C1 and C2 (pF)
Recommended Range for
12 - 22
12 - 22
12 - 22
–
XTAL2 (TOSC2)
XTAL1 (TOSC1)
GND
Additional Delay
14CK + 4.1 ms
14CK + 4.1 ms
14CK + 65 ms
14CK + 65 ms
(V
from Reset
CC
14CK
= 5.0V)
(3)
(2)
(1)
(2)
(1)
(2)
CKSEL0
CKSEL3...1
0
0
0
0
1
CC
100
101
110
111
), the CKDIV8
(2)
Table 8-3
SUT1...0
(1)
00
01
10
11
00
Table
29